Sudden cardiac arrest is a leading cause of death in developed countries in the Western World, like United States and Canada. To increase the chance for survival from cardiac arrest, Cardio Pulmonary Resuscitation (“CPR”) and heart defibrillation should be given in the first few critical minutes after the incident. CPR is performed to ensure a sufficient flow of oxygenated blood to vital organs by external compression of the chest combined with rescue breathing. Heart defibrillation is performed to re-establish normal heart rhythm by delivery of an external electric shock.
The quality of CPR is an important factor in survival rate. To maximize the chances for survival, chest compressions must be given with a minimum of interruptions, and be of sufficient depth and rate. Performing chest compressions manually is an extremely exhausting task, and it is practically impossible to give manual CPR of sufficient quality during transportation of a patient. To overcome this problem, a number of automatic and manual mechanical external chest compression devices for cardiopulmonary resuscitation have been developed. For example, a device available from Michigan Instruments provides for automatic mechanical external chest compressions using a vertical column attached to a base plate. Compressed gas (oxygen or air) drives the device, and the device may include a ventilator for ventilating the patient. This device is described in U.S. Pat. Nos. 6,171,267 and 5,743,864. A cantilevered arm with a cylinder and piston assembly slides up and down on a column to compress the chest of a patient. The system comprises a measuring device to measure the depth of the patient's chest (thorax) compressions. The depth may be compared to a table in order to adjust the compression depth to each patient. This leads to delay in start-up of the compressions, and the procedure does not compensate for possible chest collapse during therapy.
U.S. Patent Publication No. 2003181834 describes another chest compression apparatus. The device comprises a back plate positioned behind the patient's back posterior to the patient's heart. The device also includes a front part for positioning around the patient's chest anterior to the patient's heart. The front part comprises two legs, which can be coupled to the back plate. The front part comprises a compression unit that automatically compresses or decompresses (lifts) the patient's chest. The width and compression depth of the apparatus is fixed and cannot be adapted to each patient. This device is gas driven, which means that it is large and heavy to use due to the need for a supply of compressed gas. Compressed oxygen may substitute for compressed air, for example, if the supply of compressed air becomes depleted, but this substitution may lead to an increased risk of fire.
U.S. Pat. No. 6,398,745 shows another example of an automatic CPR-device. This device uses a compression belt extending around the chest of a patient. The belt is repetitively tightened and relaxed through the action of a belt-tightening spool powered by an electric motor. The motor is controlled by a control system that times the compressions and controls the compressions through an assembly of clutches and brakes connecting the motor to the belt-tightening spool. The compression belt compresses and decompresses the chest of a patient, but it can easily get caught in the patient's clothes. For this reason the patient must be unclothed before the chest compression procedure can start, and valuable time is lost. The belt also covers a large area of the patient's chest and can thus interfere with defibrillation electrodes. Further, use of this deice requires that either the defibrillator electrodes be arranged on the patient prior to the arrangement of the belt or that the belt be removed before defibrillation can take place. The belt also makes use of a stethoscope to check for correct intubation and adequate rise cumbersome.
The above-mentioned devices have limitations in use, and even though automatic mechanical CPR is well documented to deliver adequate circulation to the brain and heart during CPR, such systems have not been widely used by medical personnel. The reasons for this are, among others, that they either are complicated and time-consuming to apply, cumbersome to install and operate, and/or are unstable on the chest. They are further heavy and expensive to purchase. There is therefore a need for a resuscitation device that is easy to use, rugged, portable and light weight, safe and reliable, has an intuitive user interface, ensures patient stability and has an affordable price.